Atlantea is deceptively hard.

OK, so i am a Promethean , just got to lv 90, wanted to do tartarus. first, i had to do atlantea. literally dozens of people were waiting on the tartarus sigil, but i was the only one on atlantea. so i soloed. it was actually incredibly easy until the last 2 battles. the 1st, the ice kraken things spammed legions, towers, and frozen armors on each other, went first all 3 battles against them. then, once they ar pretty much invulnerable, they attack nonstop with frost giants and stun u. the ice helephants w/ balefrost. it took me three tries. then in the Poseidonbattle i went first. they once again spammed towers, legions, and armors, while Poseidon shredded me apart with storm damage before i could use more than a fairy to heal. i didn't even go back for another try.

Could somebody give me advice and/or help me here? from the look of the sigil, tartarus will be moderately easy, with three others.